Specilization on a certain genre of games is usually because the staff is specialized on certain genres and rarely for brand identity. "We know how to create games of a certain genre, so we keep doing it". But when you think your team is capable of developing a game in a different genre, don't let your brand identity get in the way. Take Blizzard Entertainment, for example, who jumped from puzzle-platformer to racing to action-platformer to real-time strategy to action-rpg to mmorpg to virtual collectible card game to first person shooter.
Having a good reputation will greatly increase the sales of your next game. You can expect that your name alone will cause some people to buy your next project when they wouldn't have bought it otherwise due to bad ratings.
However, you can expect that after publishing a clunker, your reputation might suffer from then on, and your games after that might sell worse.
Another factor to consider when you release an AO (adults-only rated) title under the same company label as your previous games, you might get trouble to advertise both that game and your non-AO titles together on your company website. It might get your whole company website labeled as porn and get blocked by censorship programs, even those sub-pages which don't mention your pornographic games at all.
Also many payment, advertisement and digital distribution providers refuse to work with pornographers. This might make it more difficult for you when your business model depends on them. (Edit: As of September 2018, Steam is now allowing pornographic games. Edit2: Although, as of November 2018, they keep delisting some games, apparently if the characters look too young for their comfort. I would recommend anyone who considers to release a pornographic game for Steam to wait a while until Valve made clear where they draw the lines).
And then certain game journalism outlets have become increasingly conscious of sexism lately and might boycot reporting about your non-porn games when your company is also known for producing pornographic titles.
For example, the reason Koei Tecmo stated why they won't release Dead of Alive Xtreme 3 outside of Asia is because that they are afraid of media backlash affecting their brand negatively (and that game isn't even pornographic - just full of bikini babes). Another publisher, HuniePot, responded to this with an offer: "sell the distribution rights to us. We don't care when people call us pervs".